WEDNESDAY, Oct. 12 (HealthDay News) -- Black Americans who have surgery for stage 2 and stage 3 colon cancer have worse overall and recurrence-free survival rates than whites, a new study finds.
Researchers analyzed data from nearly 15,000 black and white colorectal cancer surgery patients who took part in 12 clinical trials conducted in North America between 1977 and 2002. All the patients received the same adjuvant -- or additional -- colon cancer therapy after surgery.
Over five years, black patients had a 4.6 percent lower overall survival rate and a 3.7 percent lower recurrence-free survival rate.
Black patients, however, did have a similar recurrence-free interval, or the time in which they were cancer-free before seeing their cancer return, as whites.
The survival differences between black and white patients are mostly likely due to factors unrelated to a patient's response to post-surgical treatment, said Greg Yothers, of the U.S. National Surgical Adjuvant Breast and Bowel Project Biostatistical Center, and colleagues.
"Biological differences, differences in general health, and disparities in health care outside the clinical trial are possible explanations for these findings," the researchers wrote in a journal news release.
Staging indicates how far cancer has spread.
The study is published Oct. 12 in the Journal of the National Cancer Institute.
The findings are consistent with other studies published in the last decade, Dr. Olufunmilayo Olopade, director of the Center for Clinical Cancer Genetics & Global Health at the University of Chicago, and colleagues wrote in an accompanying editorial.
They said future studies must include information on patients' socio-demographic status, tumor biology and other health conditions. They added that primary care of colon cancer survivors should be improved and monitored in order to learn more about differences in survival after cancer recurrence, and that race-specific enrollment targets may be required for trials examining genetic markers.
Despite overall improvements in colorectal cancer survival in the United States, five-year survival rates between 1999 and 2005 were 57 percent for blacks and 68 percent for whites.
The American Cancer Society has more about colorectal cancer.
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